1. Field of the Invention
The present invention relates to an image forming apparatus aiming at speed-up of a process and a control method for the image forming apparatus.
2. Description of the Related Art
The operation of an image forming process of an MFP (Multi Function Peripheral) which is a conventional image forming apparatus will be explained.
FIG. 1 is a flow chart showing an example of the operation of the image forming process of a conventional MFP. Here, the image forming process when performing double-side print will be explained. The control unit of the MFP, upon receipt of an instruction (the start button is pressed) of image forming process setting and image forming process start from a user, executes this flow. Firstly, the control unit supplies a sheet from a cassette to an image forming unit, conveys the sheet with an image formed one side thereof by the image forming unit to an ADU (Auto Duplex Unit) (S112), and furthermore, after conveying the sheet, stops the sheet by an aligning roller (S113).
Next, the control unit judges whether the sheet tray selected as a discharge destination of the image forming process is the same as the sheet tray in use now as a discharge destination of the just prior image forming process or not (S121). When the selected sheet tray is the same as the sheet tray in use now (YES at S121), the control unit goes to Step S131. On the other hand, when the selected sheet tray is different from the sheet tray in use now (NO at S121), the control unit moves the selected sheet tray (S122).
Next, the control unit judges whether the movement of the selected sheet tray is completed or not (S131). When the movement is not completed (NO at S131), the control unit repeats Step S131. On the other hand, when the movement is completed (YES at S131), the control unit starts conveying of the sheet from the aligning roller to the image forming unit (S132). The sheet, after image forming by the image forming unit, is discharged to the selected sheet tray.
Further, as a prior art relating to the present invention, as indicated in Japanese Patent Application Publication No. 2001-282074, there is an image forming apparatus for controlling the timing of starting the operation of the image forming means according to the time required for the operation other than the image forming means and the time required for starting the image forming means.
However, as mentioned above, the control unit of the conventional MFP stops the sheet at the position of the aligning roller immediately before conveying it from the ADU to the image forming unit, moves the selected sheet tray, and at the point of time when the movement is completed, conveys the sheet to the image forming unit.
Namely, the sheet is stopped during movement of the sheet tray, so that the processing time of the MFP is increased.